In many areas waste wood products are abundant and far less expensive as fuel than fossil fuels if the wood products can be burned efficiently. On the other hand, waste wood is a relatively bulky fuel and is difficult to handle and to feed into a furnace. Wood is also difficult to burn efficiently due to the handling problems associated with feeding the wood into the furnace and the difficulties of providing uniform feeding of fuel into the furnace as well as providing efficient and consistent combustion of the wood.